#include <bits/stdc++.h>

using namespace std;

class Solution
{
public:
    int combinationSum4(vector<int> &nums, int target)
    {
        vector<size_t> dp(target + 1, 0);
        dp[0] = 1;
        for (int i = 0; i <= target; i++)
        {
            for (int j = 0; j < (int)nums.size(); j++)
            {
                if (i >= nums[j])
                {
                    dp[i] = dp[i] + dp[i - nums[j]];
                }
            }
        }
        return dp[target];
    }
};

int main()
{
    vector<int> nums{1, 2, 3};
    Solution sol;
    cout << sol.combinationSum4(nums, 4) << endl;
    return 0;
}